CHAPTER XI.
BALLOONS AND PARACHUTES.
Balloons that really go up are always attractive but by thoughtful planning they can be made much more beautiful. A nice white balloon against a blue sky is very pleasing, but most boys like more color. The hot air balloons are made of tissue paper, and consist of an inverted bag with a light piece of reed at the bottom to keep the mouth open. The most successful shape is shown by [Fig. 184]. This need not be perfectly round on top, but may be pointed, as in [Fig. 185]. If the balloon is too nearly round like a ball, it is liable to turn over and allow the hot air to escape. If the balloon is too long and slender vertically, it would probably flounder around in the breeze too much. There is not the variety possible in balloons that there is in kites, as no ballast can be attached that is of much service. In some shapes only a very little is necessary to keep them in an upright position, in this case a little ballast will suffice, and a number of shapes can be made with this addition. The ballast should be suspended by strings from the reed at the bottom, see [Fig. 186]. The ballast may only be a piece of cardboard, but in some cases that little is very necessary.
Some of the boys try models of the dirigible, but usually they get something too large for hot air manipulation. The dirigible is more of a cigar-shaped balloon. Strings run down to a framework that carries the propeller, which is a paper windmill in this case, but it is very difficult to keep these representative parts light enough to be carried by the hot air medium.
In making a balloon like [Fig. 184] the covering is made in tapering sections. The pattern given is for a five-foot balloon. The width at the lower end of the section is five inches, three feet farther up fifteen inches, and it comes to a point at the top. The edges of these sections form a long curve, [Fig. 187]. Five feet would require just a little over two lengths of tissue paper. There are seven sections in the balloon.
Figs. 184, 185, 186.
Figs. 187, 188, 189, 190.
Figs. 191, 192. [↑]
Inflation. Two methods are used to fill the balloons. A wire is stretched across the frame of the mouth of the balloon and another at right angles to it. A ball of excelsior having been soaked in paraffin is attached at the crossing of the two. The ball should be flattened into a disc about two inches in diameter and one inch in thickness. Holding the balloon up by the top the paraffin disc is lighted with a parlor match. It burns and creates heat that collects in the upper part of the balloon. When it is filled so that it lifts a little and wants to get away it is released carrying up the heat generator with it. The paraffin ball continues to furnish hot air until it burns out. A balloon so equipped will travel several blocks, high up in the air. The paraffin ball is also wound about with a very fine wire which is also used to attach the ball to the wires across the opening of the balloon. It will be seen at once that a good sized opening is necessary and in this design, the reed band is ten inches in diameter.
The other method of filling is by means of a stove pipe furnace or some similar device, but in this case all the heating is done on the ground. A hole is dug in the ground and the stovepipe is banked in as a chimney. A fire is built in the hole and the hot air goes up thru the pipe to the balloon that is suspended over it. If it was not for the stove pipe the blaze would ignite the walls of the balloon. Some quite large balloons have been sent up in this way. A piece of tin or sheet iron is good to make a cover for the hole in the ground so as to prevent the dirt from falling in on the fire. Some use a little oil on the fire, but there should not be too much else the blaze will reach up thru the pipe so far as to burn up the balloon. It is well to have a cord above so as to hold the balloon up and if it is too high to hold with the hand, a pole with a wire on the end of it that could be readily released might be used. As the bag gets inflated it is best to remove the pole and hold to the bottom by the hands.